Over the years, portable electronic devices such as smartphones and handheld games have become prevalent. Some of these devices are known to incorporate ambient light sensors, which typically are mounted to printed circuit boards and include light guides or lenses for exposing the sensors to ambient light. Unfortunately, the light guides and lenses can tend to negatively impact the cost of the devices and limit the placement and/or configuration of various device features. For instance, a sensor window typically must be included for mounting of a lens, which can restrict the placement of other components.